Adaptive Audio Detector for Fast, Frequency-Independent Limiting
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Solution Overview
Problem
Dynamic processors face challenges in achieving fast response times without frequency dependency, leading to potential speaker or hearing damage from loud and impulsive sounds like gunshots, as traditional methods either fail to be effective on impulsive noises or introduce frequency-dependent errors.
Innovation Solution
A fully adaptive dynamic processor is designed with both an adaptive filter and a fixed filter in the adaptive detector, along with an adaptive module that includes a second adaptive filter, allowing for fast response times and uniform, non-frequency dependent limiting through the use of logarithmic functions and adaptive time constants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional dynamic processors use fast response time settings, then the response speed is improved, but frequency-dependent errors are introduced that cause incorrect output limiting
Solution Approach 1:
The patent implements adaptive time constants that dynamically adjust based on signal characteristics. The detector uses an adaptive filter that modifies its time constant according to the input signal frequency and amplitude, allowing fast response for impulsive sounds while maintaining frequency-independent accuracy for continuous signals. This dynamic adaptation resolves the contradiction by making the response time flexible rather than fixed.
Solution Approach 2:
The system changes the time constant parameter adaptively based on signal conditions. For impulsive noises like gunshots, the time constant is reduced to enable fast response, while for frequency-sensitive applications, the time constant is adjusted to eliminate frequency dependency. This parameter adaptation allows the system to optimize both response speed and accuracy for different operating conditions.
2Measurement precision
If traditional dynamic processors reduce frequency dependency, then output accuracy is improved, but response time increases making the processor ineffective for impulsive noises
Solution Approach 1:
The adaptive detector implements dynamic time constant adjustment that responds to signal characteristics in real-time. When impulsive signals are detected, the system automatically reduces the time constant for fast response. When continuous signals are present, the time constant is optimized for frequency independence. This dynamic behavior allows the system to achieve both fast response and frequency independence as needed.
Solution Approach 2:
The system performs preliminary detection of signal characteristics (impulsive vs. continuous, frequency content) before applying the appropriate time constant setting. This preliminary analysis allows the adaptive filter to pre-adjust its parameters to match the incoming signal type, ensuring optimal performance before the actual processing occurs.
3Measurement precision
If traditional methods adapt portions of the dynamic processor, then some frequency dependency is reduced, but the methods are neither fast enough for impulsive noises nor slow enough to remove all frequency-dependent errors
Solution Approach 1:
The patent implements a fully adaptive detector where the time constant is continuously adjusted based on signal characteristics. Unlike traditional methods that use fixed or partially adaptive approaches, this system dynamically optimizes the time constant for each signal condition, achieving both fast response for impulsive noises and complete frequency independence for continuous signals. The adaptive filter structure enables this full adaptation across all operating conditions.
Solution Approach 2:
The system uses feedback from the detector output to continuously adjust the adaptive filter parameters. The detector monitors signal characteristics and feeds this information back to modify the time constant and filter settings in real-time. This closed-loop feedback mechanism ensures the system automatically optimizes its response time and frequency independence based on the actual input signal conditions.
Data Source
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AI summary
A dynamic processor (102) for compressing an incoming audio signal is provided. The processor includes an adaptive detector (105), an adaptive module (110), and an amplifier (115). The adaptive detector (105) includes a first adaptive filter (135) and is configured to apply a transfer function to the incoming audio signal to generate a detector output signal. The adaptive module (110) includes a second adaptive filter (175) and is configured to generate a control signal based on the detector output signal. The amplifier (115) is configured to receive the control signal from the adaptive module and to generate a compressed audio signal based on the control signal.